A common method for the manufacture of asphalt shingles is the production of a continuous strip of asphaltic shingle material followed by a shingle cutting operation which cuts the continuous strip into individual shingles. In the production of asphaltic strip material, either an organic felt or a glass fiber mat is passed through a saturator, containing liquid asphalt at a very hot temperature, to form a saturated asphaltic strip. Subsequently, the hot asphaltic strip is passed beneath a granule applicator which applies the protective surface granules to portions of the asphaltic strip material. In conventional shingle processes, the hot asphaltic strip material is next directed toward a cooling section where the asphaltic strip is held in the form of numerous loops. The cooling section of existing processes acts as an accumulator or temporary storage means for the asphaltic strip prior to shingle cutting and packaging. The asphaltic strip is maintained in the cooling section for a short period of time during which the asphaltic strip is cooled by the effects of the factory air acting on the loops. Some production processes provide for fans for blowing factory air through the loops, in a direction generally parallel to the lengths of material in the loops, and generally perpendicular to the machine direction of the shingle production machine. Some production processes use a water spray to wet the asphaltic strip prior to the blowing of air through the loops.
One of the problems associated with existing shingle production processes is that during the summer months, when factory air is at elevated temperatures and can be well over 100.degree. F., the cooling section is insufficient to cool the asphaltic strip to the degree required for proper cutting and packaging of the shingles. This is especially true in relatively warm climates, such as the southern portion of the United States. The problem of inability to cool the shingle can also be bothersome in cool weather because outside cooling air applied to the asphaltic strip can evaporate and hold much less moisture than warm air can. If the asphaltic strip is too hot, the shingle cutting operation is adversely affected. Also the shingle packaging operation becomes less efficient when the shingles are too hot, and hot shingles become a greater fire hazard once they are packaged. Also, it is desirable to avoid packaging wet shingles. As new technology is applied to existing shingle production facilities, the speed with which the continuous asphaltic strip can be produced is increased. Thus, it has been found that in many cases the limiting factor in increasing the speed and the efficiency of a shingle production machine is the ability to cool and dry the asphaltic strip prior to cutting and packaging.
One of the attempts to solve the problem of cooling asphaltic strip material is disclosed in U.S. Pat. No. 2,365,352, to Moffitt. Moffitt describes a continuous asphaltic strip production process in which the cooling section contains a single water spray means for spraying water onto the loops of shingles as the loops are formed in the cooling section. Moffitt also provides for blowing cooling air through the loops, in a direction parallel to the strip material, while the loops are in the cooling section. Moffitt's solution to the asphaltic strip cooling problem is disadvantageous in that the air flow is not perpendicular or normal to the asphaltic strip material and is, therefore, relatively inefficient. The relatively inefficient nature of Moffitt's cooling system necessitates a rather lengthy cooling section in the machine direction. Also, in part due to the inefficiency of the air flow, Moffitt's system requires an enclosed cooling section, which greatly increases the capital expense of the apparatus.
A cooling system proposed for solving the above problem of cooling asphaltic strip material provides for the use of repeated applications of spraying an evaporative liquid such as water onto the asphaltic material, with each application of evaporated liquid being followed by air jets impinging onto the asphaltic strip material in a direction normal to the strip material to evaporate the liquid, thereby cooling and drying the strip material. This proposed cooling system for cooling strip material is highly dependent on temperature and humidity conditions of the air being impinged upon the strip material. The higher the relative humidity of the air used to evaporate the liquid, the greater the difficulty in obtaining substantially complete evaporation of the liquid. Also, colder air is able to hold less moisture than warm air, and thus, the temperature affects the evaporation of the liquid. There is a need for a method and apparatus for cooling asphaltic strip material in which the ability of the air jets impinging on the asphaltic strip material to evaporate the liquid on the strip material is taken into account.